1. Technical Field
The present invention relates to a vibrator device, an oscillator including the vibrator device, a gyro sensor, an electronic apparatus, and a vehicle.
2. Related Art
In general, a quartz crystal oscillator mounting a vibrator, particularly, a quartz crystal vibrator is used widely as a reference frequency source of a consumer apparatus such as a mobile communication apparatus such as a mobile phone, a radio wave timepiece, and an IC card.
Since the quartz crystal vibrator is supported by a conductive adhesive or the like in a package, in a case where an ambient temperature of the quartz crystal vibrator changes, the hysteresis occurs due to an occurrence of a thermal distortion caused by a difference in a thermal expansion coefficient with a container (package) in a supporting portion supporting a quartz crystal vibrator element, and further, a difference in a degree of recovery of the thermal distortion between the supporting portion and the quartz crystal vibrator element in a case where the temperature of the quartz crystal vibrator returns to an original temperature. That is, a hysteresis phenomenon of temperature characteristics occurs such that it requires a long time for a frequency of the quartz crystal vibrator to return to an original frequency due to a stress from the supporting portion even when the temperature of the quartz crystal vibrator returns to the original temperature, or there is a difference in frequency-temperature dependence of the quartz crystal vibrator at a rise and fall of the temperature when the temperature of the quartz crystal vibrator changes reciprocally between t1 and t2.
JP-A-2014-33368 discloses an oscillator that supports the quartz crystal vibrator element on a pedestal portion having the same material as the quartz crystal and fixes the pedestal portion to the container in order to reduce the thermal distortion caused by the difference in the thermal expansion coefficient between the quartz crystal vibrator element and the pedestal portion, and to suppress the hysteresis in the frequency of the quartz crystal vibrator due to the temperature change, and oscillates a stable reference frequency.
The oscillator disclosed in JP-A-2014-33368 can suppress the hysteresis in the frequency of the quartz crystal vibrator with the distortion caused by the difference in the thermal expansion coefficient between the pedestal portion of the quartz crystal and the quartz crystal vibrator element due to the temperature change. However, since the distortion caused by the difference in the thermal expansion coefficient between the container and the pedestal portion of the quartz crystal cannot be reduced, there is a problem that the hysteresis in which the vibration characteristics with respect to the temperature changes cannot be reduced sufficiently.